US1681146A - Apparatus for curing tires under internal pressure - Google Patents

Description

Aug. 14, 1928.

F. B. PFEIFFER APPARATUs F012 CURING TIRES UNDER INTERNAL PRESSURE original Filed Feb. 2s, 1923 ...nu l

Patented Aug. 14, 1928.

FRED BROWN PFEIFFER, OF AKRON, OHIO.

APPARATUS FOR CURING TIRES UNDER INTERNAL PRESSURE.

Application led February 23, 1923, Serial No. 620,701. Renewed June 16, 1928.

My invention relates to an apparatusfor curing tires under internal fluid pressure of any suitable fluid such as air, water or steam, whereby im roved results are obtained in the manu acture of these articles.

My invention relates to the inflatable cores or air bags for use in'expanding and forming pneumatic 4tire casings which are so constructed as to obtain improved results in the curing of tires.

The general purpose of this invention is to provide an improved core for expanding the so-called' drum built or flat band tire casings from a transversely flat annulus into the shape of a tire, whereby the principal expanding operation is performed without linjuriously stretching or elongat'.

in vthe beads.

eretofore an` ordinary inner tube has been used for this purpose or an air bag constructed ori-the sameA rinciple as an inner tube with layers of fdbric reinforcement 'arranged with its threads diagonally of the tube and crossing. Such tubes or bags in use prior to my invention expand under internal pressure in all directions from their longitudinal axis. They are commonly suported upon a core or rim Ato prevent them om expanding inwardly, but too much lateral expansion occurs and correspondingly less circumferential elongation. It is the latter actionin the bag that is necessary to stretch or expand the flat band casing into the form of a tire and 'to bring the beads as close together as ossible.

My invention is esigned to provide an air bag in which the objectionable qualities of the ordinary bag are obviated so that a flat band casing may be expanded thereon to stretchl it circumferentially throughout its tread portion. A

Another purposeof my invention is to rovide an airbag which will first-expand into *a fixed or predetermined rounded cross-sectional contour and then elongate throughoutits outer circumferential portion. Still another purpose of my invention is to provide a bau which will function in the manner above described without the use of a support. so that it may be used without a chuck or stand and without the use of the usual bead clamping rings which are required to hold the beads as in processes in use prior to my invention.

Other objects and advantages, such as simplicityI of construction and relatively low cost of manufacture, will presently appear when the following description i's read and upon reference to the drawings and appended claims.

In the drawings which accompany and form a part of this specification:

Figure 1 is a bag constructed 1n accordance with vention;

` Figure 2 is a transverse sectional view of the bag drawn on an enlarged scale;

Flgure 3 is a view, partly in section and partly in elevation, illustrating the manner in which the tire is shaped by the use of the lmproved, process using the improved expansible core;

Figure 4 is a fragmentary view, partly in section, further illustrating the operation of the invention; and

Figure 5 is a transverse sectional view showing the bag and tire fully expanded.

In the drawings, the'numeral 1 designates the air bag and 2 an unexpanded flat band casing mounted thereon, the bag being shown deflated in Figures 1, 2 and 3 and expanded in Figures/l and 5.

The air ba 1 is constructed preferably in the form oig an annulus. It comprises, in its broad aspect,` a casing 3 of rubber or rubber composition reinforced at close intermy inperspective view of anair r vals by transversely extending reinforcing elements such as cords 4 or other subsantially inextensible units. The cordsA 4 are preferably disconnected one from the other .and are arranged to additionally reinforce the inner circumferential portion 5 of the bag and preferably thev casing 3 is increased in thickness throughout this latter portion.

I prefer` to form the casing 3 of oord fabricsuch as is usedl in the construction of tires, although this is not essential to my invention. As best shown in Figure 2, the cord fabric is arranged in layers 6 and 7l laid around an Ordinar inner tube 8 of rubber or rubber composltion with the cords of the fabric extending transversely or at right angles to the plane of the tube and with the edges of the layers overlapping, as

at 9, so that the cords 4 additionally reinforce 'the inner circumferential portion of the casin The valve 10 of the inner tube projects t rough the layers 6 and 7 as shown 1n Figure 1. The bag thus formed is vulcanized to unite the overlapping edges of the layers and to Vform a composite structure of the layers 6 and 7 and the tube 8.

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The casing is provided with its central or major portion in the form of a cylinder 11, and with its edges containing the usual beads 12 which in the.form shown are the usual soft or stretchable clincher beads.

The action of this bag under internal pressure is as follows:

It is first distended to a substantially circular shape in cross-section as shown in dotted lines in Figure 3. The arrangement of the cords throughout the inner circumference of the bag and the increased thickness of rubber preventlateral stretch throughout the zone of the bag and also longitudinal elongation to any material dc- -gree. The remainder of the bag is free to stretch laterally to the extent of stretch inherent in the cords, but the greater degree of stretch occurs throughout this portion in a longitudinal direction through separation of the cords into a fan-like formation as shown in Figure 4. This action of thecords permits the bag to elongate or stretch longitudinally throughout its outer circumferential portion so that said portion increases in circumference While the inner circumferential portion remains substantially fixed.

In shaping a flattire band totire form by -expanding it, this is precisely the action desired as it is necessary that thenbeads and adjacent portions of the side-walls remain unstretched and that-the tread zone of the 4band be'elongated a considerable degree to bring it to the outer circumferential measurement of a tire. As before stated, it is diicult to accomplish this operation successfully with ordinary forms ofair bags andl by processes in use prior to my invention.

Although the foregoingdescription has been somewhat detailedin attempting to irnpart a clear understanding of my invention, it is not to `be construedin a .restrictive l riphery.

band or on a transverselyfcurved core, the

beads have been st-retcheduponthe exertion of the expanding pressure. This action isl prevented orflimlted by the use of the core described, and it is not necessary to use any bead clamping rings.

VVhatI claim is: Y l 1. An air bag for use in bringingl tires without exerting. stretching action upon' the beads of the tire, comprising an expansible core and a plurality of non-extensible reinforcing members about said core and ar# ranged at rightangles to the plane of the tire, the bag being free j'to expand circumferentially along its outer periphery, the reinforcing members being disconnected from one another so as to permitfthem to spread durin the expansion of the bag, the bag being tickened along its inner pe- 2. An air bag for use in shaping pneumatic tire casings, comprising an expansible tubular ring of rubber anda plurality of -non-stretchable cords, all of which are parfrom a flat band condition to tire shapel allel and arranged transversely of? the tube,

said cords being more numerous about the inner circumference of the tube than'about its outercircumference, whereby .the tubev mayv expand c1r :umferential1yv 'but be re-A stricted from expansion tranversely. l FRED BROWN PFEIFFER.A

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